Droplet generator and method of servicing extreme ultraviolet radiation source apparatus

Abstract

An extreme ultraviolet radiation source apparatus includes a chamber including at least a droplet generator, a nozzle of the droplet generator, and a dry ice blasting assembly. The droplet generator includes a reservoir for a molten metal, and the nozzle has a first end connected to the reservoir and a second opposing end where molten metal droplets emerge from the nozzle. The dry ice blasting assembly includes a blasting nozzle, a blasting air inlet and a blaster carbon dioxide (CO 2 ) inlet. The blasting nozzle is disposed inside the chamber. The blasting nozzle is arranged to direct a pressurized air stream and dry ice particles at the nozzle of the droplet generator.

What is claimed is: 
     
       1. A method for removing residual material from an extreme ultraviolet (EUV) radiation source, the method comprising:
 generating target droplets of a given material in a droplet generator through a nozzle of the droplet generator; 
 monitoring residual material on the droplet generator to measure an amount of the residual material; and 
 removing the residual material by ejecting pressurized dry ice particles based on the measured amount of the residual material. 
 
     
     
       2. The method of  claim 1 , wherein microscopic shock waves by the pressurized dry ice particles remove the residual material from the target droplet generator. 
     
     
       3. The method of  claim 1 , further comprising:
 forming the pressurized dry ice particles. 
 
     
     
       4. The method of  claim 3 , further comprising:
 forming a pressurized air stream from a cleaner supporting member. 
 
     
     
       5. The method of  claim 1 , wherein removing the residual material further comprises collecting the residual material and sublimated gaseous carbon dioxide from the pressurized dry ice particles. 
     
     
       6. The method of  claim 1 , further comprising:
 adjusting valves of a blasting pump when an amount of the residual material in the droplet generator is more than a threshold amount; and 
 regulating operating parameters of a blasting compressor and the blasting pump. 
 
     
     
       7. The method of  claim 1 , wherein a flow rate of the pressurized dry ice particles ejected through a cleaner blasting nozzle is in a range from 0.5 liters per minute to 500 liters per minute. 
     
     
       8. The method of  claim 1 , wherein a pressure of the pressurized dry ice particles ejected through a cleaner blasting nozzle is in a range of 1 kPa to 1000 kPa at the nozzle. 
     
     
       9. The method of  claim 1 , wherein the pressurized dry ice particles ejected through a cleaner blasting nozzle have a diameter in a range from about 10 μm to about 10 mm. 
     
     
       10. A method for removing residual material in an extreme ultraviolet (EUV) source, the method comprising:
 generating target droplets of a given material in a droplet generator through a nozzle of the droplet generator; 
 removing the residual material by a cleaner blasting assembly having a cleaner blasting nozzle; and 
 adjusting a pressure of pressurized dry ice particles of the cleaner blasting assembly based on an amount of the residual material removed. 
 
     
     
       11. The method of  claim 10 , further comprising an exhaust device configured to collect the residual material. 
     
     
       12. The method of  claim 10 , further comprising:
 adjusting a pulsation insert configured to generate a pulsation of pressurized air stream of the cleaner blasting nozzle. 
 
     
     
       13. The method of  claim 10 , further comprising:
 adjusting a supporting member including a blasting compressor. 
 
     
     
       14. The method of  claim 10 , further comprising:
 adjusting valves of a blasting pump when the amount of the residual material in the droplet generator is more than a threshold amount. 
 
     
     
       15. The method of  claim 10 , further comprising:
 regulating ejecting parameters of a blasting compressor and the blasting pump, when pressurized dry ice particles are ejected from a cleaner blasting nozzle. 
 
     
     
       16. The method of  claim 10 , wherein the cleaner blasting assembly is selectively attachable to and extendable from a chamber. 
     
     
       17. A cleaning apparatus for an extreme ultraviolet (EUV) radiation source, comprising:
 a cleaner blasting assembly having a cleaner blasting nozzle to remove residual material from a target droplet generator; 
 an imaging device configured to monitor the residual material on the droplet generator; and 
 a controller communicating with the cleaner blasting assembly and the imaging device configured to adjust cleaning modes and position of the cleaner blasting assembly to enhance the cleaning effect. 
 
     
     
       18. The cleaning apparatus of  claim 17 , wherein the controller regulates ejecting parameters of a blasting compressor and the blasting pump, when pressurized dry ice particles are ejected from the blasting nozzle. 
     
     
       19. The cleaning apparatus of  claim 18 , wherein the controller stops the ejection of the pressurized dry ice particles when an amount of the residual material on the droplet generator is below a threshold amount. 
     
     
       20. The cleaning apparatus of  claim 17 , wherein the controller further include an exhaust device to collect the residual material and sublimated gaseous carbon dioxide from pressurized dry ice particles.